Expression of Vitreoscilla haemoglobin in hybrid aspen (Populus tremula × tremuloides)

Abstract

SummaryWe describe the first ever expression of Vitreoscilla haemoglobin (VHb) in an economically important boreal woody plant hybrid aspen ( Populus tremula × tremuloides ). VHb has mainly been expressed in biotechnologically important unicellular organisms of both prokaryotic and eukaryotic origin. VHb expression, in this study, was analysed under different greenhouse cultivation conditions and under elevated UV-B illumination.Microscope analyses of leaves grown under optimized conditions revealed significant differences both in cell structure and size when the transgenic VHb lines were compared with the control lines. VHb lines displayed a higher relative volume of mitochondria and a significantly enhanced accumulation of starch in chloroplasts, all of which pointed towards changes in cellular energy production. Under elevated UV-B illumination, the differences between VHb lines became evident. Some specific VHb lines had elevated levels of total flavonoids, individual quercetin, kaempferol-and myricetin-derivatives relative to controls and other transgenic lines. This observation may reflect the availability of extra energy resources for secondary metabolite production and possibly an enhanced protection ability of these transgenic lines against UV-B illumination. Thus, all these findings point to changes in the energy metabolism of VHb lines. In the cultivation conditions tested this observation did not, however, result in a general improvement of elongation growth.

GMO Safety Assessment-Feasibility of Bioassay to Detect Allelopathy Using Handy Sandwich Method in Transgenic Plants

“…3). These may be of some effects of different production level of metabolic substances in the similar way like other transgenic aspen where the concentrations of total flavonoids, quercetin, kaempferol and myricetin derivatives in the leaves were different between control and transgenic trees (Haggman et al, 2003).However, we did not detect statistically significant differences among transgenic and control trees by analysis of variance (P > 0.12). In contrast, there was a statistically significant difference between species Populus and Eucalyptus with allelopathy (P < 0.002) which indicated the feasibility of the sandwich method to detect the different allelopathy level between species.…”

Axillary buds are dwarfed shoots that tightly regulate GA pathway and GA-inducible 1,3-β-glucanase genes during branching in hybrid aspen

“…Hybrid aspen (clone T89) was first grown in vitro under sterile conditions for 4–5 weeks (photoperiod 18h, light intensity 28 µmol m −2 s −1 , temperature 20 o C). Explants of these plants were used for Agrobacterium -mediated transformation (Häggman et al , 2003). Briefly, 3–5mm long internodal stem segments were cut and placed on solid callus production medium, hereafter referred to as MS1 [half-strength Murashige and Skoog (1/2× MS) medium; Duchefa, M0222], which contained 2% sucrose, 0.5 µM 6-benzylaminopurine (BAP; Sigma B3408), 4 µM 2,4-dichlorophenoxyacetic acid (2,4-D; Fluka, 31518), and 0.7% agar (pH 5.6).…”

Transcriptome sequencing of transgenic poplar (Populus × euramericana 'Guariento') expressing multiple resistance genes

“…This molecule transfers oxygen to the respiratory chain, regulates the activity of terminal oxidase, alters the efficiency of oxidative phosphorylation and metabolic pathways under hypoxic conditions, and promotes cell growth and the expression of some genes [68]. The expression of the vgb gene can increase the effective oxygen concentration in a plant and enhance chlorophyll biosynthesis [69,70] and can also promote plant growth [71,72], improve waterlogging resistance [73], and increase the detoxification capacity of plants [74]. We detected 21 differentially expressed genes encoding oxygen metabolic pathway enzymes, including nine (five glutaredoxin-related proteins, two thioredoxins, and two multicopper oxidases) that were up-regulated and 12 (three carbonic anhydrases, two peroxidases, two ferric reduction oxidases, three oxidases, and two iron/ascorbate family oxidoreductases) that were down-regulated.…”